Burnt wires

My middle console went up in smoke and i smelt a burnt rubber smell i ripped off the cover and found tht. Two cables had there insulation completley incinertaed and they were red hot . wen seperated they cooled don and wen they touch it sparks. Up . its a 2004 impala 1 of the wires was broken. . i jus want to know why this happend and price of fix .

Rear defrost/defog stopped working a few weeks ago. Since this back window
was replaced (a stick impaled the seal when a branch fell on the car a couple
of years ago-and the seal is part of the wind...